<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml">

<head>
  <title>HTML5 GetUserMedia Demo</title>
  <meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0" />
</head>

<body>
  <input type="button" title="开启摄像头" value="开启摄像头" onclick="getMedia();" /><br />
  <video height="120px" autoplay="autoplay"></video>
  <hr />
  <input type="button" title="拍照" value="拍照" onclick="getPhoto();" /><br />
  <canvas id="canvas1" height="120px"></canvas>
  <hr />
  <input type="button" title="视频" value="视频" onclick="getVedio();" /><br />
  <canvas id="canvas2" height="120px"></canvas>

  <script type="text/javascript">
    var video = document.querySelector('video');
    var audio, audioType;

    var canvas1 = document.getElementById('canvas1');
    var context1 = canvas1.getContext('2d');

    var canvas2 = document.getElementById('canvas2');
    var context2 = canvas2.getContext('2d');

    navigator.getUserMedia = navigator.getUserMedia || navigator.webkitGetUserMedia || navigator.mozGetUserMedia ||
      navigator.msGetUserMedia;
    window.URL = window.URL || window.webkitURL || window.mozURL || window.msURL;

    var exArray = []; //存储设备源ID
    // MediaStreamTrack.getSources(function (sourceInfos) {
    // for (var i = 0; i != sourceInfos.length; ++i) {
    // var sourceInfo = sourceInfos[i];
    // //这里会遍历audio,video，所以要加以区分
    // if (sourceInfo.kind === 'video') {
    // exArray.push(sourceInfo.id);
    // }
    // }
    // });

    function getMedia() {
      if (navigator.getUserMedia) {
        navigator.getUserMedia({
          'video': {
            'optional': [{
              'sourceId': exArray[1] //0为前置摄像头，1为后置
            }]
          },
          'audio': true
        }, successFunc, errorFunc); //success是获取成功的回调函数
      } else {
        alert('Native device media streaming (getUserMedia) not supported in this browser.');
      }
    }

    function successFunc(stream) {
      console.log(stream)
      //alert('Succeed to get media!');
      if (video.mozSrcObject !== undefined) {
        //Firefox中，video.mozSrcObject最初为null，而不是未定义的，我们可以靠这个来检测Firefox的支持
        video.mozSrcObject = stream;
      } else {
        video.srcObject = stream //window.URL && window.URL.createObjectURL(stream) || stream;
      }

      //video.play();

      // 音频
      audio = new Audio();
      audioType = getAudioType(audio);
      if (audioType) {
        audio.src = 'polaroid.' + audioType;
        audio.play();
      }
    }

    function errorFunc(e) {
      alert('Error！' + e);
    }


    // 将视频帧绘制到Canvas对象上,Canvas每60ms切换帧，形成肉眼视频效果
    function drawVideoAtCanvas(video, context) {
      window.setInterval(function () {
        context.drawImage(video, 0, 0, 90, 120);
      }, 60);
    }

    //获取音频格式
    function getAudioType(element) {
      if (element.canPlayType) {
        if (element.canPlayType('audio/mp4; codecs="mp4a.40.5"') !== '') {
          return ('aac');
        } else if (element.canPlayType('audio/ogg; codecs="vorbis"') !== '') {
          return ("ogg");
        }
      }
      return false;
    }

    // vedio播放时触发，绘制vedio帧图像到canvas
    // video.addEventListener('play', function () {
    // drawVideoAtCanvas(video, context2);
    // }, false);

    //拍照
    function getPhoto() {
      context1.drawImage(video, 0, 0, 90, 120); //将video对象内指定的区域捕捉绘制到画布上指定的区域，实现拍照。
    }

    //视频
    function getVedio() {
      drawVideoAtCanvas(video, context2);
    }
  </script>
</body>

</html>